Impact device for driving horizontal holes in soft ground



Nov. 12, 1968 B. v. SUDNISHNlKOV ET IMPACT DEVICE FOR DRIVING HORIZONTALHOLES IN SOFT GROUND Filed Sept. 16, 1966 E x v; w s a I Z V M $3 MUnited States Patent Ofice 3,410,354 Patented Nov. 12, 1968 3,410,354IMPACT DEVICE FOR DRIVING HORIZONTAL HOLES IN SOFT GROUND BorisVasilievich Sudnishnikov, Krasny prospekt 56, kv.

61; Konstantin Konstantinovich Tupitsyn, Ulitsa Derzhavina 19, kv. 57;Konstantin Stepanovich Gurkov, Ulitsa Derzhavina 19, kv. 28; AlexandrDmitrievich Kostylev, Ulitsa Derzhavina 19, kv. 44; Vladimir VasilievichKlimashko, Ulitsa Novogodnyaya 44, kv. 23; and Vladimir DmitrievichPlavskikh, Ulitsa Kamenskaya 84-v, kv. 33, all of Novosibirsk, U.S.S.R.

Filed Sept. 16, 1966, Ser. No. 580,014 4 Claims. (Cl. 173-125) ABSTRACTOF THE DISCLOSURE An impact device in which a striker acts on a bodyunder the action of compressed air which is fed to a cavity in the rearof the striker. The striker has holes in a wall enclosing the cavity tocause retraction of the striker after the impact. A step bushing isfixed in the body to periodically close the holes in the wall of thestriker and a flange with holes is secured in the rear of the body forexhausting spent air.

The present invention relates to air-driven impact devices for forminghorizontal holes in soft ground, say, in subgrades of motor roads or inpermanent ways of railroads.

More specifically, this invention relates to impact devices in which thestriker, accelerated by compressed air, imparts a striking impact to thebody of the device, thus ensuring its penetration into the ground.

Devices of such a type are known, but their extensive utilization isrestricted because of numerous inherent disadvantages.

Very often on stopping the device inside a hole, it cannot be startedagain, and the ground has to be excavated in order to extract thedevice. If it proves impracticable to open the hole, e.g., in the caseof a paved concrete road, the device has to be abandoned therein. Suchan unreliability of the device results chiefly from the air-distributingmeans which does not ensure the reliable starting of the device in anyposition of its striker, even with the use of an additional means as astarting valve which fails to ensure the sufficient fast-response.

Frequently soil is admitted into the device and causes jamming of thestriker in the body.

An object of the present invention is to eliminate the abovedisadvantages.

Another object of. the present invention is to provide an improvedair-distributing mechanism which ensures the reliable starting of thedevice in any position of its striker, as Well as the stable andreliable operation of the device.

The air-distributing mechanism, according to the present invention, isessentially a two-stepped bushing disposed in the tail part of a bodyand connected to an air supply main, and to holes in the wall of acavity in the tail part of the striker which are periodically closedwith said bushing during the displacement of the striker.

It is expedient to connect the bushing, by a tubular elastic member, toa flange rigidly secured to the tail part of the body and provided withholes for expulsion of exhausted air. Such a connection of bushing to aflange makes it possible for the bushing to move somewhat with respectto the body in case of its bending when the device passes by anobstacle.

To prevent particles of soil from getting into the device, the flange isprovided with an elastic valve which does not interfere with the exhaustof the used air.

Other advantages of the present invention will become more fullyapparent from a consideration of the following description of anexemplary embodiment thereof, taken in conjunction with the appendeddrawing which shows a cross-sectional view of a device in conformitywith the present invention.

A tubular body 1, one end of which is pointed, accommodates a striker 2composed of a sleeve 3 and a rod 4 rigidly connected to each other bymeans of a conical member 5. The forming of the striker 2 as a compositeunit is expedient by reason of the fact that the composite striker isconsiderably less rigid as compared with that made in one piece, and itimparts a smaller load to the body 1 with the same magnitude of thestriking impact, thus increasing the service life thereof.

The sleeve 3 rests with its collars 6 and 7 on the inner surface of thebody 1, so that between said body 1 and said collars there is a radialclearance ensuring the free travel of the striker 2 in case of possiblebending of the body 1. The rear collar 7 is provided with packing rings8, whereas the collar 6 is provided with longitudinal grooves 9 to passthe compressed air.

In the tail part of the striker 2, there is a cavity 10 formed by wallsof the sleeve 3, which periodically communicates with the workingchamber 11 of the device through holes 12 in the sleeve 3. The cavity 10permanently communicates with the air supply main 13 through a cavity ina two-stepped bushing 14 and a duct 15 in a flange 16 rigidly secured inthe tail part of the body 1.

The bushing 14 is connected at one end to the flange 16, whereas itsopposite end is disposed in the cavity 10 to ensure periodical closingof the holes 12 during the travel of the striker 2.

An elastic pipe 17 allows for the bushing 14 to be self-adjusted in caseof bending of the body 1 When it meets large stones or cavities in itsway.

On feeding the compressed air into the cavity 10, the striker 2 beginsto travel inside the body 1, and at the end of its stroke imparts astriking impact to body 1, resulting in advancing the body 1 into theground.

The moment the bushing 14 opens the holes 12, the air from the airsupply main through the cavity 10 begins to fill the working chamber 11,thus acting on the striker 2.

Due to the difference of surface areas of the butt ends of the striker 2acted upon by the compressed air, the striker 2 begins to travelrearwards until the holes 12 pass the edges 18 of the bushing 14.

As soon as the holes 12 pass the edges 18 of the bushing 14, the air inthe chamber 11 will be exhausted through holes 19 in the flange.Thereafter the process is repeated.

To prevent foreign particles from getting into the device, use is madeof a plate elastic valve 20 secured on the pipe 17, which does notinterfere with the exhaust of the air used in the chamber 11.

The device is retained in the hole due to forces of friction between thebody 1 and the Walls of holes.

The above-said solutions of engineering problems make it possible toconsiderably increase the service life of the device and ensure about500 hrs. of guaranteed operation with an impact energy of 18 to .20kg.-m. and a frequency of impacts about 380 to 400 impacts per minute.

What is claimed is:

1. An impact device for forming horizontal holes in soft groundcomprising a body, a striker slidably disposed in said body forimparting impact to said body by the action of a pressure fluid, saidstriker having a rear portion Witha cavity and with holes in a wallenclosing said cavity; a step bushing fixed in said body andcommunicating with a supply of pressure fluid, said bushing beingmounted in said cavity of the striker to periodically close said holesin the wall of said cavity when the striker is displaced, a flangerigidly secured in the rear portion of said body and provided with holesfor exhausting spent fluid and a tubular elastic member on said body atsaid flange.

2. A device according to claim 1, wherein said elastic member includeselastic valve means for preventing foreign particles from entering thebody through said holes in said flange.

3. A device as claimed in claim 2, wherein said striker comprises a rodand a surrounding sleeve coupled together as a composite assembly.

4. A device as claimed in claim 3 wherein said sleeve includes collarswhich locally contact the body and pro- 4 vide radial clearance betweenthe body and the sleeve in regions outside said collars.

References Cited UNITED STATES PATENTS 711,859 10/1902 Holden 173-4251,005,770 10/1911 Clark 17592 FOREIGN PATENTS 1,000,310 1/1957 Germany.

JAMES A. LEPPINK, Primary Examiner.

